Allowance for Credit Losses (Aging Analysis of Past Due Loans and Leases) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Loans and Leases Excluding Covered Current	$ 100,459	[1]	$ 99,099	[1]
Loans and Leases Excluding Covered 30-89 Days Past Due	952	[1]	1,223	[1]
Loans and Leases Excluding Covered 90 Days Or More Past Due	375	[1]	408	[1]
Nonaccrual Loans and Leases Excluding Covered	1,843	[1]	1,872	[1]
Total Loans And Leases Excluding Covered Loans	103,629	[1]	102,602	[1]
Commercial and Industrial [Member]
Loans and Leases Excluding Covered Current	35,407		35,746
Loans and Leases Excluding Covered 30-89 Days Past Due	62		85
Loans and Leases Excluding Covered 90 Days Or More Past Due	2		2
Nonaccrual Loans and Leases Excluding Covered	685		582
Total Loans And Leases Excluding Covered Loans	36,156		36,415
Commercial Real Estate - Other [Member]
Loans and Leases Excluding Covered Current	10,204		10,273
Loans and Leases Excluding Covered 30-89 Days Past Due	26		22
Loans and Leases Excluding Covered 90 Days Or More Past Due	1		0
Nonaccrual Loans and Leases Excluding Covered	312		394
Total Loans And Leases Excluding Covered Loans	10,543		10,689
Commercial Real Estate - Residential ADC [Member]
Loans and Leases Excluding Covered Current	1,503		1,671
Loans and Leases Excluding Covered 30-89 Days Past Due	8		14
Loans and Leases Excluding Covered 90 Days Or More Past Due	0		0
Nonaccrual Loans and Leases Excluding Covered	312		376
Total Loans And Leases Excluding Covered Loans	1,823		2,061
Commercial Other Lending Subsidiaries [Member]
Loans and Leases Excluding Covered Current	3,681		3,589
Loans and Leases Excluding Covered 30-89 Days Past Due	14		25
Loans and Leases Excluding Covered 90 Days Or More Past Due	5		4
Nonaccrual Loans and Leases Excluding Covered	16		8
Total Loans And Leases Excluding Covered Loans	3,716		3,626
Direct Retail Lending [Member]
Loans and Leases Excluding Covered Current	14,540		14,109
Loans and Leases Excluding Covered 30-89 Days Past Due	135		161
Loans and Leases Excluding Covered 90 Days Or More Past Due	48		55
Nonaccrual Loans and Leases Excluding Covered	139		142
Total Loans And Leases Excluding Covered Loans	14,862		14,467
Retail Revolving Credit [Member]
Loans and Leases Excluding Covered Current	2,125		2,173
Loans and Leases Excluding Covered 30-89 Days Past Due	20		22
Loans and Leases Excluding Covered 90 Days Or More Past Due	14		17
Nonaccrual Loans and Leases Excluding Covered	0		0
Total Loans And Leases Excluding Covered Loans	2,159		2,212
Retail Residential Mortgage [Member]
Loans and Leases Excluding Covered Current	20,424	[1]	19,393	[1]
Loans and Leases Excluding Covered 30-89 Days Past Due	479	[1]	570	[1]
Loans and Leases Excluding Covered 90 Days Or More Past Due	290	[1]	310	[1]
Nonaccrual Loans and Leases Excluding Covered	320	[1]	308	[1]
Total Loans And Leases Excluding Covered Loans	21,513	[1]	20,581	[1]
Retail Sales Finance [Member]
Loans and Leases Excluding Covered Current	7,509		7,301
Loans and Leases Excluding Covered 30-89 Days Past Due	50		75
Loans and Leases Excluding Covered 90 Days Or More Past Due	13		18
Nonaccrual Loans and Leases Excluding Covered	15		7
Total Loans And Leases Excluding Covered Loans	7,587		7,401
Retail Other Lending Subsidiaries [Member]
Loans and Leases Excluding Covered Current	5,032		4,807
Loans and Leases Excluding Covered 30-89 Days Past Due	158		248
Loans and Leases Excluding Covered 90 Days Or More Past Due	1		1
Nonaccrual Loans and Leases Excluding Covered	44		55
Total Loans And Leases Excluding Covered Loans	5,235		5,111
Other Acquired [Member]
Loans and Leases Excluding Covered Current	34		37
Loans and Leases Excluding Covered 30-89 Days Past Due	0		1
Loans and Leases Excluding Covered 90 Days Or More Past Due	1		1
Nonaccrual Loans and Leases Excluding Covered	0		0
Total Loans And Leases Excluding Covered Loans	35		39
Government Guaranteed Loans [Member]
Loans and Leases Excluding Covered 30-89 Days Past Due	82		91
Loans and Leases Excluding Covered 90 Days Or More Past Due	$ 218		$ 206

[1] Residential mortgage loans include $82 million and $91 million in government guaranteed loans 30-89 days past due, and $218 million and $206 million in government guaranteed loans 90 days or more past due as of March 31, 2012 and December 31, 2011, respectively.